Screw thread gauge



Nov. 26, 1935. POND SCREW THREAD GAUGE Filed Dec. 13, 1932 mvmran By CMF nd A TTUBNEY Patented Nov. 26,

Pratt & Whitney Company Hartford, Conn a corporation oi New JerseyApplication nic -1m 1s, 1932, Serial No. 647,005

6 Claim.

This invention relates to screw thread gauges and particularly to agauge for testing screw -threads having freelyrotatable rolls formingthe, gauging elements which are provided with screw threads on theirwork engaging surfaces.

An object of the present invention is to provide freely rotatable rollsin a screw thread snap gauge having threaded portions upon theircylindrical outer surfaces which form the-gauging elements of the rolls,these screw threads having the same lead as the screw threads to begauged but being of the opposite hand.

Another object of the invention is to provide means to vary the axialposition of the rotatable rollers so that in any rotative position theywill properly contact with screw threads being gauged, each rotativeposition having a definite axial position.

And finally it is an object of the invention to provide cam meanspreferably formed upon one end of the rolls and engaging an abutment onthe gauge frame whereby the rolls as they are rotated will be axiallymoved engaging positions.

A feature which enables me to accomplish the above named objects is thata positioning'pin is mounted in the gauge frame which engages an endface of a roll and a spring forces the roll axially so that itsface-engages this pin, the end face of the. roll engaging the pin beingprovided with a helicoidal surface corresponding in lead to that of thethreads formed upon its cylindrical surface.

with the above and other objects in'view my invention includes thefeatures 01 construction and operat on setforth in thefollowing-specifiing.

In the accompanying drawing annexedhereto f cation and illustrated inthe accompanying drawand forming a part of this specification, I haveshown my invention embodied in a screw thread gauge of the type shown inpatent to Johnson,

No. 1,660,335 dated February 28, 1928, but it willbe understood that theinvention can be otherwise embodied and that the drawing is not to' be'construed as defining or limiting the scope of the invention, the claimsappended tothe specification being relied upon for that purpose.

. In the drawing:

Figure 1 is a side elevation of a complete gauge partly broken away tomore clearly show a part of the construction.

Fig.- 2, is an end view of the gauge looking di- 7 r n amount determinedby the lead of the thre ed portions of the.

rectly toward the gauging surfaces of the rollers.

Fig. 3 is an oblique view of one of the threaded rolls forming a workengaging member and showing the cam surface upon one end face; and

v Fig. 4 is an isometric view of a roll engaging spring;

In the above mentioned drawing I have shown but. one embodiment of theinvention which is now deemed preferable-but it is to be understood-thatchanges and modificat ons may be made within the scope of 'theappendedclaims without departing from the spirit of the invention.

r Briefly and in its preferred aspect, my invention may include thefollowing principalparts: 15 I First, a generally U-shaped frame havingrolls mounted transversely within the. opposite arms, one or more pairsof rolls being in opposed rela- 'tion to each'other; second, supportingmeans for rotatably supporting the rolls in position, these 29 meanspreferably permitting adjustment to vary the distance apart of. opposingrolls; 'third,.abutments in the frame controlling the ax al ppsitions ofthe rolls and preferably adjustable so' that these positions maybe'accurately deter- 25 mined; fourth, spring means resiliently holdingthe rolls against ther abutments; and fifth, cam means on the end faceof the rolls, engaging its abutment, preferably in the form of aheliooidalv "surface, corresponding in lead to the lead of-go the screwthreads on the rolls so that as the rolls are rotated by engagement withworkpieces being tested the position of the work engaging surfaces ofthe'rolls will'always be correctly-disposed;

Referring more in detail'to the figures of the draw ng; .1 provide aU-shaped frame III of the same general type as that shown and described.in the above 'mentioned patent to Johnson. Within the opposite arms ofthis frame it) are 40 mounted transverse pins ll preferably havingeccentric portions such "as are clearly shown anddescribed in theabove-mentioned Johnson pat ent. Upon this eccentric portion threadedwork engaging rolls l2 may be mounted for free rotation; As theconstruction of the pin II and its eccentric portion is or may besimilar to that described in the above mentioned patent, furtherdescription is not thought to be necessary. It will be noted, however,that the rolls l2 in the present invention have upon their outercylindrical surfaces screw threads i3 extending throughout their length.These screw threads l3 have the same -lead as the screw threads to aroll l2. Preferably and as shown, this pin l .varied axially of the rollI2.

2 7 be tested, but have their helix vof .the opposite hand. The gaugeshown in Fig. 2 having lefthand threads is therefore designedparticularly for g'auging right-hand threads.

As rotation of the threaded roll the position of the grooves and ridgesforming the part of the threads l3 directly engaging the screw threadsbeing tested, means are provided,

for maintaining these positions correctly for any rotative positionassumed by the rolls. For that purpose springs H of generally flat leafform engage one end of a roll l2 and force it axially toward theopposite face of the frame l0. Limitingthe movement of the rollsindirection is an abutment IS, the position of which may be slightlyvaried so that the rolls l2 for any one rotative position .may becorrectly determined.

As shown in Figs. 1 and 2, this abutment l5 comprises a pin formed onthe inner end of .a short screw threaded member 16 threaded into a sideof the frame Ill so that the inwardly extending pin portion i5 thereofengages an end face of a is formed somewhat eccentrically relative tothe axis of ,the member. lli'so that by rotating the screw it theposition of the pin will be slightly In any adjusted position the screwit may be locked by a short check screw l1 bearing upon the outer end ofthe screw I6.

when a roll I 2 is correctly adjusted for'one rotative position it willbecorrect' for all rotative positions.

In operation the pins ll supporting a pairof rolls I! are adjusted forthe proper distance apart,

for gauging, a particular size and type of screw threads and the pins l5are so adjusted that the 7 threads upon the rolls I! will properlyintermesh with corresponding grooves and ridges of the screw threadsbeing tested. Thus adjusted the rolls I! may rotate due to engagement ofthe work being tested during the gauging operation but in any rotativeposition of the rolls If they will be in proper mating relation forengagement withscrew threads being tested.

In Fig. la supplementary pair of rolls I8 is I shown which may beprovided with gailgm surfaces for testing a diameter or other functionnot requiring screw threads on its surface.

I: would vary aoeaoeo What I claim is: h 1. A screw thread gaugecomprising in combination, a U-shaped frame, opposed screw threadedrolls rotatably supported in opposite arms of said frame, means toadjust the distance 5 apart of said rolls, and means to cause axialmovement of said rolls in timed relation to their rotation.

2; A screw thread gauge comprising in combination, a. frame, opposedscrew threaded rolls l0 rotatably supported in said frame, means to setsaid rolls for predetermined gauging dimensions, resilient meansnormally holding said rolls toward one axial position, said rolls havinga helicoidal surface at one end and means on said frame engagingsaidhelicoidal surface whereby said rolls are caused to move axially asthey are rotated. v v

3. A screw thread gauge comprising in combination, a frame,opposed-gauging elements sup;

ported within said frame one of which elements. is a screw threaded rollrotatably mounted in said frame and having screw threads on its outercylindrical surface of the same lead as the screw threads to be tested,said rolls having a helfcoidal surface on one end, resilient meansforcing said rolls in one direction, and means engaging said surface andcoacting with said resilient means causing said roll to move axially inaccordance with its lead as it is rotated.

a 4. A screw thread gauge comprising in com- 4 bination, a frame,opposed gauging elements within said frame one of which elements is ascrew threaded roll, means to support said roll for rotation-about itsaxis, means to adjust the axial position of said'roll, and means tocause axial movement of said roll in accordance with the lead of itsscrew threads as the roll is rotated. '5. A screw threadgaugecomprisin'gin combination, a frame, opposed gauging elements 40.

within said frame, one of whichelements is a I screw threaded rollhaving the same lead as the screw threads to be gauged and'being freelyrotatable about its 'axis, a, spring engaging one end and normallyforcing said roll axially in one direction, and a pin engaging theopposite end of said roll for limiting said movement, the endface ofsaid roll-engaging said pin having a helicoidal surface corresponding inlead to the screw threads on said roll whereby rotation of said rollforces said roll axially .and maintains the screw threads on the roll incorrect gauging position.

6. A screw thread caliper gauge comprising a frame, a pair of 0Dposing,screw threaded, freely rotatable gauge rollers in said frame, one ofsaid 5 rollers being axially displaceable and springcontrolled. I

CHARLES M. POND.

